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Students at a Dublin technology university are enjoying an unexpected benefit from artificial intelligence – it’s helping to heat up their campus.
Since 2023, TU Dublin Tallaght has become one of a growing number of campuses Buildings in the city’s southwestern suburbs will be heated by waste heat from a nearby Amazon Web Services data center.
Data centers have always produced excess heat, but integration into district heating networks has been slow because the waste heat generated by these power-hungry facilities is often too cold to directly heat other buildings.
Things are changing now. As the artificial intelligence boom takes hold and data centers increasingly fill racks with advanced chips that require three times the computing power, operators must find new ways to balance maximizing efficiency without sacrificing sustainability.
Adam Fabricius, commercial manager at heating, ventilation and air conditioning equipment supplier Sav Systems and heating network researcher at sister company EnergiRaven, said artificial intelligence is a “twist” that makes it more attractive.
“What’s exciting is that AI can give you higher temperatures, and water cooling makes it easier. There’s a lot less hardware required to connect these systems,” he told CNBC.
Brendan Reidenbach of the International Energy Agency told CNBC that supplying heat to district heating networks could provide “additional social license” for data centers.
“On paper it may not end up being very cost-effective, but it does help turn the potentially bad news of data center additions into the good news of ultimately decarbonizing heating, which has a good social impact. So it’s very much a win-win situation,” he added.
Ireland is a ‘blank slate’
Big tech companies are receptive to this. Microsoft Plans announced to fuel Denmark’s Høje-Taastrup district heating network; a Equinics Data center heats 1,000 homes in Paris; and Google announced a major Heat recovery project Factory in Hamina, Finland.
Ireland is one of two European countries to suspend new data center deployments as power-hungry facilities put pressure on Dublin’s grid, draining electricity 22% of the power of small countries 2024. Ireland eventually eased its moratorium late last year as the AI boom caused a U-turn in perceptions of the economic potential of these facilities.
The IEA’s Redenbach said Ireland was “effectively a blank slate” because the country had no previous district heating system. He said the Tallaght plan showed the benefits of integrated planning as it brought together power system operators and distribution network operators.
In 2020, the local government established Heat Works, Ireland’s first not-for-profit energy utility company. Waste heat from nearby AWS data centers provides 100% of the heat for the network.
“While our monitoring is only in its second year, we have evidence that the project overall limits our exposure to market price shocks,” Rosie Webb, director of decarbonization at TU Dublin, told CNBC via email.
TU Dublin calculates that the campus will have saved approximately 704 tonnes of CO2 by 2024, despite the additional energy demand brought about by the addition of two new buildings on campus.
AWS’s data center in Tallaght offers a “unique opportunity” to reuse heat, the company’s country director Niamh Gallagher said. The scheme, which will provide heat recovery free of charge from AWS, will initially heat 55,000 square meters of public buildings – three times the size of the city’s Croke Park stadium – as well as commercial space and 133 apartments.
“When we can identify a special project that leverages our infrastructure to support a community’s climate goals, it’s a win-win,” Gallagher told CNBC.
Keep hot chips cool
Ben Hertz-Shargel, global head of grid edge at energy research firm Wood Mackenzie, said Europe is much more advanced than the United States when it comes to heating networks.
Some medium-sized data centers located near metropolitan areas may be best suited to provide waste heat, Hertz-Shargel said. He added that one example is Equinix, which, like AWS, does not profit from the waste heat it provides.
However, delays in permitting and the high capital expenditure costs of building a heating network and integrating data centers into the system make scaling the model challenging.
There is also the problem of life cycle mismatch. Reidenbach said that district heating networks typically have a service life of 30 years, while equipment in data centers is only seven to 10 years old. “That does leave a very large risk of stranded assets,” he added.
We think of data centers as energy borrowers, but in fact they are also energy producers.
Kenneth O’Mahony
CEO of Nisarus
Nexalus, a thermal and scientific engineering company whose technology was patented by Trinity College Dublin, Ireland, is researching ways to capture heat from hot GPUs and CPUs within data centers.
The company uses jet impingement liquid cooling to enhance the chip’s performance while capturing waste heat at higher temperatures. Nexalus CEO Kenneth O’Mahony told CNBC that the system does not produce “low-grade” heat, but instead provides heat of about 55 to 60 degrees Celsius without the use of a heat pump, which is hot enough to be reused directly for district heating.
The company said other data centers typically emit excess heat at around 30 to 35 degrees Celsius, making repurposing it much less feasible. The company also maps how much heat the chip emits so it can target the hottest areas for cooling.
“It’s like a shower head in a shower. If your shoulder hurts, you can turn it to where you want it. That’s what we do, we plan it to maximize the impact on each individual chip,” O’Mahony said.
“We view data centers as energy borrowers and indeed energy producers,” he added. “The desire should be to embed your data centers into the construction phase of the city, into the design of the apartment buildings… to provide adequate heat for the entire building.”
Nexalus isn’t the only company exploring this technology. NVIDIA Recently, it caused panic in the cooling market when it launched its product. Next generation Rubin chip Doesn’t require quite as much cooling as earlier models.
Rob Pfleging, CEO of modular liquid cooling provider Nautilus Data Technologies, said he got “chills” when he saw Nvidia’s announcement because he has long focused on increasing water temperatures to achieve “significant improvements in efficiency.”
“The great thing about (Nvidia’s) announcement is that it’s moving in the right direction because it can now also repurpose that heat more easily,” Pfleging told CNBC.
future challenges
Cities outside Ireland are also looking to adopt this model. British officials visited Denmark in October to see how data centers connect to district heating networks and learn from the Nordic countries’ success. The UK hopes to expand the scale of its heating network so that it accounts for 20% of the country’s heating needs from the current 3%.
Analysis by EnergiRaven and Danish energy consultancy Viegand Maagøe found that waste heat from data centers could provide enough heat for at least 3.5 million homes by 2035 if heating networks were expanded in parallel with AI infrastructure.
Matthew Powell, who conducts research at EnergiRaven, believes that using excess heat as community power could effectively allow electrons to be used twice.
“For every kilowatt of energy we reuse, there is a kilowatt of energy that we don’t need to import,” Fabricius said, adding that it would have further geopolitical and economic significance if it could replace natural gas.
“You do a calculation with it and then you use it again to heat people’s homes, that heat would have been generated by natural gas if it was a boiler,” he told CNBC.
Asked about the risks of relying on private data centers to provide core energy, TU Dublin said Tallaght district heating system was not dependent on a single source. The university is exploring geothermal energy and plans to adopt a range of renewable energy sources to further diversify its energy mix.
Nonetheless, the scheme now covers 92% of the campus’s heating needs and, according to the university, has significantly accelerated TU Dublin’s progress towards its 2030 decarbonisation targets.
Currently, district heating meets around 10% of global building heating needs, 90% of which comes from fossil fuels. EnergiRaven’s Fabricius said that in order for countries like the UK to take advantage of the reuse of waste heat, we need to move away from gas and put the right infrastructure in place underground.
System diversification “may be the best approach, but it will be painful. It won’t be easy,” Fabricius said., But take the UK, for example, which is about to say “we actually need to do something different”.
